JERUSALEM: The Australian suspected of spying for Mossad was left hanging in the bathroom of his cell for more than an hour by prison guards who had ''fallen asleep on the job'' and failed to keep watch on the inmate known to them as ''Prisoner X'', Israeli media reported on Thursday.

Not one of the guards instructed to look at the monitors displaying the images captured by security cameras in his cell noticed 34-year-old Ben Zygier take a sheet from his bed into the shower stall after he ate dinner at 7pm on December 15, 2010, an Israeli Prisons Service source told the newspaper, Yedioth Ahronoth.

At least an hour had passed when they realised Mr Zygier, who was being held in solitary confinement after being arrested by Israel's internal security services, Shin Bet on February 24, 2010, was nowhere to be seen.

They rushed to his cell, cut him down and tried to revive him, as did medics who arrived soon after, but he was pronounced dead at the scene.

A report from the judge who led the inquiry into his death says the time of death was listed as 8.19pm.

Prisons Service officials told Yedioth Ahronoth the guards had ''fallen asleep on the job … they were busy with something else''.

Advertisement

''The bottom line is that the prisoner died, and we failed at our job of keeping him alive, despite all the difficulties involved in guarding a prisoner who is cut off from all members of the prison staff he comes into contact with.''

Because Mr Zygier was kept in such secrecy - where only ''four or five high-ranking Prisons Service officials knew who the man was, what his job was and what the allegations against him were'' - the usual admissions processes for prisoners had not been observed, the source said.

He had not undergone psychological evaluation to determine whether he was suicidal, the paper reported.

''We couldn't handle him like every other prisoner who receives a professional diagnosis and therapy,'' the source said.

Fairfax Media revealed Mr Zygier, who had migrated to Israel in 2000 and travelled to Australia to change his name and passport at least three times, was under Australian Security Intelligence Organisation surveillance at the time of his arrest and was suspected, along with two other dual Australian-Israeli citizens, of spying for Mossad.

His identity was revealed last week in an ABC Foreign Correspondent program, and since then, the Israeli government has partially lifted the gag order preventing the release of details about his arrest, detention and death.

It is still not known what work he did for Mossad, why he was arrested and what led Israel to keep him jailed in secrecy under a false name for the 10 months before his death.